1. Field
Example embodiments relate to three-dimensional (3D) color display apparatuses using a volume hologram. Also, example embodiments relate to 3D color display methods.
2. Description of the Related Art
Among methods of displaying 3D images, a 3D scanning method, a holographic method, and/or a stereoscopic method may be well known in the art. According to the holographic method, an interferogram may be formed in a photosensitive material using a reference beam and an object beam with coherence to form a 3D image. When the reference beam is irradiated onto the 3D image, the object beam may be restored to display the 3D image. According to the holographic method, a coherent light source may be required and it may be difficult to record/reproduce a large object located far away. According to the stereoscopic method, two two-dimensional (2D) images having a binocular disparity may be respectively viewed by left and right eyes of a viewer, thereby making the image stereoscopic. According to the stereoscopic method, two plane images may be used, and thus, it may be easy to realize a 3D image and/or to display the 3D image having a high resolution. However, since the stereoscopic method only uses a horizontal parallax, it may be difficult to realize a 3D image having both a horizontal parallax and a vertical parallax.
On the other hand, according to the 3D scanning method, a beam emitted by a light source may be directly modulated in order to improve optical efficiency and/or contrast of the image. In a 3D image displaying apparatus using the 3D scanning method, point scanning may be realized in a 3D manner, or an image may be scanned in a 2D manner in x- and y-directions using a spatial light modulator and the image may be realized in the 3D manner by moving a focus in a z-direction. When the 3D scanning method is performed using a 2D spatial light modulator, the scanning may be performed at high speed; however, fabrication costs may increase. On the other hand, the point scanning method may be inexpensive and may require only simple equipment. Point scanning may be realized only when one-dimensional optical modulation can be performed in a proceeding direction of the light beam.